This is an artist's concept of Jupiter's moon Europa, at right, with a water-ice plume erupting from its limb. Astronomers using NASA's Hubble Space Telescope have found a plume-like feature imaged in 2014 and 2016, which corresponds to the location of an unusually warm spot on the moon's icy crust seen in the late 1990's by the Galileo spacecraft. Researchers speculate that this might be circumstantial evidence for water venting from a subsurface ocean believed to be present beneath the moon's frozen crust.